It's an intricate network of waterways that feeds countless rivers, including the Ganges — the longest river in India. More than 400 million people live in the Ganges Basin alone.

Like many glacial regions, though, global warming is changing the Himalayas. Some areas of the range, like the Karakorum region, might be growing, as shown by this NASA animation tracking growth from 1990 to 2015:

Yet many more are shrinking, including the Imja Glacier in Nepal. Scientists are keeping an eye on these natural wonders to see how the region reacts to a changing climate — from both space and the ground.

Association for Comparative Alpine Research, Munich. 2007 photo taken by Alton Byers; courtesy of the Archives of Alton Byers and the Mountain Institute